Friday, December 27, 2013

Two Views of Recent (2000-2012) Forest Fires in the American Southwest

Imaging and recording forest fire extent serves a number of important roles in forest ecology and is also very useful for planning vacations!  (Don't plan to camp in a recently burned forest)  There are now two ways of mapping recent fire locations.
The USFS ForWarn Forest Change Assessment Viewer (FCAV) can visualize fires that burned from 2000-2012 using the Fire Perimeter Layer.
 The Global Forest Change map (GFC) (Hansen et al) is a new tool that shows global forest extent (green),  deforestation (red), and aforestation (blue) and reforestation (purple).  In the high-resolution image above, one can match USFS fire perimeters to the actual burn scars, as well as visualize total forest extent.  Beetle die-off is apparently not apparent in this view.

But why isn't the 2011 Horseshoe Two fire visible? This large stand-replacement fire burned more than 70% of the Chiricahua mountains (look for a green tear-drop shape near the Southern edge of the map above).  It is clearly visible as a red blob in the USFS image, but not in the Global Forest Change map.   It is clearly visible on Landsat images:
Image source.

Zoomed in images show the disparity:

 The USFS viewer shows the entire range as burned area.

But hardly any forest loss is recorded on the GFC map.  Why??

Perhaps the discrepancy is due to burn severity?  Fires do not burn evenly across a landscape, and many regions within a burn perimeter may be only lightly or moderately burned.  

Here is the Horseshoe Two fire burn severity map, clearly showing large areas of high and moderate intensity fire within the burn perimeter:


An important note about the colors shades on the GFC map:  they indicate the percent forest (defined as vegetation over 5m) per grid cell.

This view of the Rodeo-Chediski (2002) fire shows different shades of red, and green.  No regrowth is apparent.

Zooming in all the way to individual pixels shows the different shades.  Assuming the forest loss shades are proportional to the initial forest cover shades, the lightest red colors indicate areas that were 75-100% forest (and now are not forest or are 0-25% forest), the light grey-red indicates areas that were 50-75% forest (and now are not forest or are 0-25% forest), the darker grey-red indicates areas that were 25-50% forest (and now are not forest or are 0-25% forest), and black  indicates areas that are (and continue to be) 0-25% forest.  

What about the 2002 Biscuit fire in the Klamath-Siskyou region....
Purple in the GFC map above may indicate some regrowth (and/or replanting) in the 10 years following the fire.

Tuesday, December 10, 2013

New Science of Predator Control: Unexpected (emergent) Outcomes

Predator control has been based on the simplistic thinking that fewer lions or wolves would mean more deer and elk.  Therefore, many states promote over-hunting predators.  Interestingly, recent research from Washington State University's Dr. Wielgus and coworkers has reversed conventional wisdom: "Heavy hunting can result in higher overall density of cougars, increased predation on game, and more frequent conflicts with people -- in short, the exact opposite of what was intended." (quoted in National Geographic, Dec. 2013 "Cougars Make a Comeback")

A Range Overlap of the Pinyon Pines in central AZ

In which mountain range could one find three different U.S. Pinon Pine species (P. cembroides, P. edulis, and P. monophylla)?

Trick question!

Surprisingly, not a major mountain range, but the low hills surround Aravaipa Canyon.  This area may be an important biogeographical linkage between the sky island mountain ranges to the south, dominated by Mexican Pinyon (Pinus cembroides) and the larger mountains to the north, dominated by Pinus edulis.  Pinus monophylla is more of a Colorado plateau and California mountain species, but with weird disjunct populations as far South and East as the Florida mountains near Deming, NM!  

Specimen collection data from SEINet.

BEFORE and AFTER views of the proposed Rosemont Mine

The Final Environmental Impact Statement (EIS) for the proposed Rosemont Mine was released Nov. 29th.  In addition to containing thousands of pages detailing the effects of this open pit copper mine on the ecology of the Santa Rita mountains, the report also contains a number of simulated "before-and-after" images of the mine.  

This view shows the Santa Rita mountains as they appear today.

This view shows the Santa Rita mountains after the Rosemont open-pit mine ("preferred alternative").

This is another view of the Santa Rita mountains as they appear today.

This is the same view after the construction of the Rosemont open pit mine ("barrel alternative").

This satellite image shows the site of the proposed Rosemont mine, situated in undisturbed rolling hills on National Forest land.  Grasslands on south- and west-facing slopes give way to oak woodlands on north- and east-facing slopes.  This view is about 5 miles on a side.

This satellite image (taken at the same scale) shows the nearby Sierrita Mine sprawling over the foothills of the Sierrita mountains.  The proposed Rosemont mine would not cover the entire footprint of the gargantuan Sierrita Mine because of the proposed use of compressed tailings piles.  However, in both mines, the main  "pit" is about a mile on a side.